The present invention relates to vertical louver systems of the type having a track and a plurality of louver carriers mounted for movement along the track and louver hangers mounted on the carriers for turning about a generally upright axis. It is common practice to provide louvers having a straight or substantially straight cross-section and when such louvers are suspended from the louver hangers, the louvers depend vertically from the hangers. However, some louvers used in vertical louver systems have non-linear cross-sectional contour and, if the non-linear cross-sectional contour is such that the center of gravity of the louver cross-sectional contour is at a point spaced from one side of the louver, the louver will not depend vertically downwardly but will instead extend downwardly at an angle to the vertical, which angle varies with the spacing of the center of gravity of the louver cross-sectional contour from the side of the louver and also with the length of the louver. Louvers which do not hang vertically not only adversely affect the overall appearance of the vertical louver system, but can also adversely affect the operation of the louver system.